Multi-speed transmission

ABSTRACT

The present disclosure provides a multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets includes first, second and ring gears. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least eight forward speeds and one reverse speed are achieved by the selective engagement of the five torque-transmitting mechanisms.

FIELD OF THE DISCLOSURE

The present disclosure relates to a multiple speed transmission, and inparticular to a multiple speed transmission capable of achieving eightor more speeds.

BACKGROUND

Multiple speed transmission use a number of friction clutches or brakes,planetary gearsets, shafts, and other elements to achieve a plurality ofgear or speed ratios. The architecture, i.e., packaging or layout of theaforementioned elements, is determined based on cost, size, packagingconstraints, and desired ratios. There is a need for new architecturaldesigns of multiple speed transmissions for achieving different ratioswith improved performance, cost, efficiency, responsiveness, andpackaging.

SUMMARY

In a first embodiment of the present disclosure, a multiple speedtransmission includes an input member, an output member, first, second,third and fourth planetary gearsets each having first, second and thirdmembers; a plurality of interconnecting members each connected betweenat least one of the first, second, third, and fourth planetary gearsetsand at least another of the first, second, third, and fourth planetarygearsets; a first torque-transmitting mechanism selectively engageableto interconnect the first member of the first planetary gearset with astationary member, a second torque-transmitting mechanism selectivelyengageable to interconnect the second member of the first planetarygearset with the stationary member; a third torque-transmittingmechanism selectively engageable to interconnect the second member ofthe second planetary gearset with the first member of the fourthplanetary gearset; a fourth torque-transmitting mechanism selectivelyengageable to interconnect the third member of the second planetarygearset with the first member of the third planetary gearset; and afifth torque-transmitting mechanism selectively engageable tointerconnect the third member of the second planetary gearset with thethird member of the third planetary gearset and the first member of thefourth planetary gearset; wherein the torque transmitting mechanisms areselectively engageable in combinations of at least three to establish atleast eight forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.

In one example of this embodiment, the input member is continuouslyinterconnected with the second member of the second planetary gearsetand the output member is continuously interconnected with the secondmember of the third planetary gearset and the second member of thefourth planetary gearset. In a second example, the plurality ofinterconnecting members includes a first interconnecting membercontinuously interconnecting the first member of the first planetarygearset with the first member of the second planetary gearset. In athird example, the plurality of interconnecting members includes asecond interconnecting member continuously interconnecting the thirdmember of the first planetary gearset with the third member of thefourth planetary gearset. In a fourth example, the plurality ofinterconnecting members includes a third interconnecting member thatdirectly connects the second member of the first planetary gearset tothe stationary member.

In a fifth example, the plurality of interconnecting members includes afourth interconnecting member continuously connected to the third memberof the second planetary gearset. In a sixth example, the plurality ofinterconnecting members includes a fifth interconnecting membercontinuously interconnecting the third member of the third planetarygearset to the first member of the fourth planetary gearset. In aseventh example, the plurality of interconnecting members includes asixth interconnecting member continuously connected to the first memberof the third planetary gearset. In an eighth example, the plurality ofinterconnecting members includes a seventh interconnecting membercontinuously connected to the first members of the first planetarygearset and the second planetary gearset. In a ninth example, the firstplanetary gearset comprises an idler planetary gearset having a firstset of pinion gears and a second set of pinions gears.

In another embodiment, a multiple speed transmission includes an inputmember; an output member; first, second, third and fourth planetarygearsets each having a sun gear, a carrier member, and a ring gear,wherein at least one of the first, second, third and fourth planetarygearsets comprises an idler planetary gearset and the input member andthe output member are each interconnected to at least one of the first,second, third, and fourth planetary gearsets; a firsttorque-transmitting mechanism selectively engageable to interconnect thesun gear of the first planetary gearset and the sun gear of the secondplanetary gearset with a stationary member; a second torque-transmittingmechanism selectively engageable to interconnect the carrier member ofthe first planetary gearset with the stationary member, a thirdtorque-transmitting mechanism selectively engageable to interconnect thecarrier member of the second planetary gearset with the ring gear of thethird planetary gearset and the sun gear of the fourth planetarygearset; a fourth torque-transmitting mechanism selectively engageableto interconnect the sun gear of the third planetary gearset with thering gear of the second planetary gearset; and a fifthtorque-transmitting mechanism selectively engageable to interconnect thering gear of the third planetary gearset and the sun gear of the fourthplanetary gearset with the ring gear of the second planetary gearset;wherein the torque transmitting mechanisms are selectively engageable incombinations of at least three to establish at least eight forward speedratios and at least one reverse speed ratio between the input member andthe output member.

In one example of this embodiment, the input member is continuouslyinterconnected with the carrier member of the second planetary gearsetand the output member is continuously interconnected with the ring gearof the third planetary gearset and the carrier member of the fourthplanetary gearset. In a second example, the plurality of interconnectingmembers includes a first interconnecting member continuouslyinterconnecting the sun gear of the first planetary gearset with the sungear of the second planetary gearset. In a third example, the pluralityof interconnecting members includes a second interconnecting memberdirectly connecting the carrier member of the first planetary gearset tothe stationary member. In a fourth example, the plurality ofinterconnecting members includes a third interconnecting membercontinuously interconnecting the ring gear of the first planetarygearset to the ring gear of the fourth planetary gearset.

In a fifth example, the plurality of interconnecting members includes afourth interconnecting member continuously connected to the ring gear ofthe second planetary gearset. In a sixth example, the plurality ofinterconnecting members includes a fifth interconnecting membercontinuously interconnecting the ring gear of the third planetarygearset to the sun gear of the fourth planetary gearset. In a seventhexample, the plurality of interconnecting members includes a sixthinterconnecting member continuously connected to the sun gear of thethird planetary gearset.

In a different embodiment, a multiple speed transmission includes aninput member, an output member; first, second, third and fourthplanetary gearsets each having a sun gear, a carrier member, and a ringgear, the input member and the output member are each interconnected toat least one of the first, second, third, and fourth planetary gearsets;a first torque-transmitting mechanism selectively engageable tointerconnect the sun gear of the first planetary gearset and the sungear of the second planetary gearset with a stationary member; a secondtorque-transmitting mechanism selectively engageable to interconnect thering gear of the first planetary gearset with the stationary member, athird torque-transmitting mechanism selectively engageable tointerconnect the ring gear of the second planetary gearset with the sungear of the fourth planetary gearset and the ring gear of the thirdplanetary gearset; a fourth torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the third planetary gearsetwith the carrier member of the second planetary gearset; a fifthtorque-transmitting mechanism selectively engageable to interconnect thethird ring gear of the third planetary gearset with the carrier memberof the second planetary gearset; a first interconnecting member of theplurality of interconnect members continuously interconnecting the sungear of the first planetary gearset with the sun gear of the secondplanetary gearset; a second interconnecting member of the plurality ofinterconnect members continuously connected to the ring gear of thefirst planetary gearset; a third interconnecting member of the pluralityof interconnect members directly connects the carrier member of thefirst planetary gearset to the ring gear of the fourth planetarygearset; a fourth interconnecting member of the plurality ofinterconnect members continuously connected to the carrier member of thesecond planetary gearset; a fifth interconnecting member of theplurality of interconnect members continuously interconnecting the ringgear of the third planetary gearset with the sun gear of the fourthplanetary gearset; and a sixth interconnecting member of the pluralityof interconnect members continuously connected to the sun gear of thethird planetary gearset; wherein the second planetary gearset comprisesan idler planetary gearset; further wherein the torque transmittingmechanisms are selectively engageable in combinations of at least threeto establish at least eight forward speed ratios and at least onereverse speed ratio between the input member and the output member.

In one example of this embodiment, when shifting from one forward speedratio into one of a successive higher and a successive lower forwardspeed ratio causes a single one of the first, the second, the third, thefourth, and the fifth torque transmitting mechanisms to disengage and asingle one of the first, the second, the third, the fourth, and thefifth torque transmitting mechanisms to engage.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present disclosure and the manner ofobtaining them will become more apparent and the disclosure itself willbe better understood by reference to the following description of theembodiments of the disclosure, taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is an exemplary block diagram and schematic view of oneillustrative embodiment of a powered vehicular system;

FIG. 2 is a diagrammatic view of an embodiment of a multiple speedtransmission;

FIG. 3 is a diagrammatic view of another embodiment of a multiple speedtransmission; and

FIG. 4 is a truth table presenting an example of a state of engagementof various torque transmitting mechanisms in each of the availableforward and reverse speeds or gear ratios of the transmissionsillustrated in FIGS. 2 and 3.

Corresponding reference numerals are used to indicate correspondingparts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present disclosure described below are notintended to be exhaustive or to limit the disclosure to the preciseforms disclosed in the following detailed description. Rather, theembodiments are chosen and described so that others skilled in the artmay appreciate and understand the principles and practices of thepresent disclosure.

Referring now to FIG. 1, a block diagram and schematic view of oneillustrative embodiment of a vehicular system 100 having a drive unit102 and transmission 118 is shown. In the illustrated embodiment, thedrive unit 102 may include an internal combustion engine, diesel engine,electric motor, or other power-generating device. The drive unit 102 isconfigured to rotatably drive an output shaft 104 that is coupled to aninput or pump shaft 106 of a conventional torque converter 108. Theinput or pump shaft 106 is coupled to an impeller or pump 110 that isrotatably driven by the output shaft 104 of the drive unit 102. Thetorque converter 108 further includes a turbine 112 that is coupled to aturbine shaft 114, and the turbine shaft 114 is coupled to, or integralwith, a rotatable input shaft 124 of the transmission 118. Thetransmission 118 can also include an internal pump 120 for buildingpressure within different flow circuits (e.g., main circuit, lubecircuit, etc.) of the transmission 118. The pump 120 can be driven by ashaft 116 that is coupled to the output shaft 104 of the drive unit 102.In this arrangement, the drive unit 102 can deliver torque to the shaft116 for driving the pump 120 and building pressure within the differentcircuits of the transmission 118.

The transmission 118 can include a planetary gear system 122 having anumber of automatically selected gears. An output shaft 126 of thetransmission 118 is coupled to or integral with, and rotatably drives, apropeller shaft 128 that is coupled to a conventional universal joint130. The universal joint 130 is coupled to, and rotatably drives, anaxle 132 having wheels 134A and 134B mounted thereto at each end. Theoutput shaft 126 of the transmission 118 drives the wheels 134A and 134Bin a conventional manner via the propeller shaft 128, universal joint130 and axle 132.

A conventional lockup clutch 136 is connected between the pump 110 andthe turbine 112 of the torque converter 108. The operation of the torqueconverter 108 is conventional in that the torque converter 108 isoperable in a so-called “torque converter” mode during certain operatingconditions such as vehicle launch, low speed and certain gear shiftingconditions. In the torque converter mode, the lockup clutch 136 isdisengaged and the pump 110 rotates at the rotational speed of the driveunit output shaft 104 while the turbine 112 is rotatably actuated by thepump 110 through a fluid (not shown) interposed between the pump 110 andthe turbine 112. In this operational mode, torque multiplication occursthrough the fluid coupling such that the turbine shaft 114 is exposed todrive more torque than is being supplied by the drive unit 102, as isknown in the art. The torque converter 108 is alternatively operable ina so-called “lockup” mode during other operating conditions, such aswhen certain gears of the planetary gear system 122 of the transmission118 are engaged. In the lockup mode, the lockup clutch 136 is engagedand the pump 110 is thereby secured directly to the turbine 112 so thatthe drive unit output shaft 104 is directly coupled to the input shaft124 of the transmission 118, as is also known in the art.

The transmission 118 further includes an electro-hydraulic system 138that is fluidly coupled to the planetary gear system 122 via a number,J, of fluid paths, 140 ₁-140 _(J), where J may be any positive integer.The electro-hydraulic system 138 is responsive to control signals toselectively cause fluid to flow through one or more of the fluid paths,140 ₁-140 _(J), to thereby control operation, i.e., engagement anddisengagement, of a plurality of corresponding friction devices in theplanetary gear system 122. The plurality of friction devices mayinclude, but are not limited to, one or more conventional brake devices,one or more torque transmitting devices, and the like. Generally, theoperation, i.e., engagement and disengagement, of the plurality offriction devices is controlled by selectively controlling the frictionapplied by each of the plurality of friction devices, such as bycontrolling fluid pressure to each of the friction devices. In oneexample embodiment, which is not intended to be limiting in any way, theplurality of friction devices include a plurality of brake and torquetransmitting devices in the form of conventional clutches that may eachbe controllably engaged and disengaged via fluid pressure supplied bythe electro-hydraulic system 138. In any case, changing or shiftingbetween the various gears of the transmission 118 is accomplished in aconventional manner by selectively controlling the plurality of frictiondevices via control of fluid pressure within the number of fluid paths140 ₁-140 _(J).

The system 100 further includes a transmission control circuit 142 thatcan include a memory unit 144. The transmission control circuit 142 isillustratively microprocessor-based, and the memory unit 144 generallyincludes instructions stored therein that are executable by a processorof the transmission control circuit 142 to control operation of thetorque converter 108 and operation of the transmission 118, i.e.,shifting between the various gears of the planetary gear system 122. Itwill be understood, however, that this disclosure contemplates otherembodiments in which the transmission control circuit 142 is notmicroprocessor-based, but is configured to control operation of thetorque converter 108 and/or transmission 18 based on one or more sets ofhardwired instructions and/or software instructions stored in the memoryunit 144.

In the system 100 illustrated in FIG. 1, the torque converter 108 andthe transmission 118 include a number of sensors configured to producesensor signals that are indicative of one or more operating states ofthe torque converter 108 and transmission 118, respectively. Forexample, the torque converter 108 illustratively includes a conventionalspeed sensor 146 that is positioned and configured to produce a speedsignal corresponding to the rotational speed of the pump shaft 106,which is the same rotational speed of the output shaft 104 of the driveunit 102. The speed sensor 146 is electrically connected to a pump speedinput, PS, of the transmission control circuit 142 via a signal path152, and the transmission control circuit 142 is operable to process thespeed signal produced by the speed sensor 146 in a conventional mannerto determine the rotational speed of the pump shaft 106/drive unitoutput shaft 104.

The transmission 118 illustratively includes another conventional speedsensor 148 that is positioned and configured to produce a speed signalcorresponding to the rotational speed of the transmission input shaft124, which is the same rotational speed as the turbine shaft 114. Theinput shaft 124 of the transmission 118 is directly coupled to, orintegral with, the turbine shaft 114, and the speed sensor 148 mayalternatively be positioned and configured to produce a speed signalcorresponding to the rotational speed of the turbine shaft 114. In anycase, the speed sensor 148 is electrically connected to a transmissioninput shaft speed input, TIS, of the transmission control circuit 142via a signal path 154, and the transmission control circuit 142 isoperable to process the speed signal produced by the speed sensor 148 ina conventional manner to determine the rotational speed of the turbineshaft 114/transmission input shaft 124.

The transmission 118 further includes yet another speed sensor 150 thatis positioned and configured to produce a speed signal corresponding tothe rotational speed of the output shaft 126 of the transmission 118.The speed sensor 150 may be conventional, and is electrically connectedto a transmission output shaft speed input, TOS, of the transmissioncontrol circuit 142 via a signal path 156. The transmission controlcircuit 142 is configured to process the speed signal produced by thespeed sensor 150 in a conventional manner to determine the rotationalspeed of the transmission output shaft 126.

In the illustrated embodiment, the transmission 118 further includes oneor more actuators configured to control various operations within thetransmission 118. For example, the electro-hydraulic system 138described herein illustratively includes a number of actuators, e.g.,conventional solenoids or other conventional actuators, that areelectrically connected to a number, J, of control outputs, CP₁-CP_(J),of the transmission control circuit 142 via a corresponding number ofsignal paths 72 ₁-72 _(J), where J may be any positive integer asdescribed above. The actuators within the electro-hydraulic system 138are each responsive to a corresponding one of the control signals,CP₁-CP_(J), produced by the transmission control circuit 142 on one ofthe corresponding signal paths 72 ₁-72 _(J) to control the frictionapplied by each of the plurality of friction devices by controlling thepressure of fluid within one or more corresponding fluid passageway 140₁-140 _(J), and thus control the operation, i.e., engaging anddisengaging, of one or more corresponding friction devices, based oninformation provided by the various speed sensors 146, 148, and/or 150.

The friction devices of the planetary gear system 122 are illustrativelycontrolled by hydraulic fluid which is distributed by theelectro-hydraulic system in a conventional manner. For example, theelectro-hydraulic system 138 illustratively includes a conventionalhydraulic positive displacement pump (not shown) which distributes fluidto the one or more friction devices via control of the one or moreactuators within the electro-hydraulic system 138. In this embodiment,the control signals, CP₁-CP_(J), are illustratively analog frictiondevice pressure commands to which the one or more actuators areresponsive to control the hydraulic pressure to the one or morefrictions devices. It will be understood, however, that the frictionapplied by each of the plurality of friction devices may alternativelybe controlled in accordance with other conventional friction devicecontrol structures and techniques, and such other conventional frictiondevice control structures and techniques are contemplated by thisdisclosure. In any case, however, the analog operation of each of thefriction devices is controlled by the control circuit 142 in accordancewith instructions stored in the memory unit 144.

In the illustrated embodiment, the system 100 further includes a driveunit control circuit 160 having an input/output port (I/O) that iselectrically coupled to the drive unit 102 via a number, K, of signalpaths 162, wherein K may be any positive integer. The drive unit controlcircuit 160 may be conventional, and is operable to control and managethe overall operation of the drive unit 102. The drive unit controlcircuit 160 further includes a communication port, COM, which iselectrically connected to a similar communication port, COM, of thetransmission control circuit 142 via a number, L, of signal paths 164,wherein L may be any positive integer. The one or more signal paths 164are typically referred to collectively as a data link. Generally, thedrive unit control circuit 160 and the transmission control circuit 142are operable to share information via the one or more signal paths 164in a conventional manner. In one embodiment, for example, the drive unitcontrol circuit 160 and transmission control circuit 142 are operable toshare information via the one or more signal paths 164 in the form ofone or more messages in accordance with a society of automotiveengineers (SAE) J-1939 communications protocol, although this disclosurecontemplates other embodiments in which the drive unit control circuit160 and the transmission control circuit 142 are operable to shareinformation via the one or more signal paths 164 in accordance with oneor more other conventional communication protocols (e.g., from aconventional databus such as J1587 data bus, J1939 data bus, IESCAN databus, GMLAN, Mercedes PT-CAN).

Referring to FIG. 2, a schematic representation or stick diagramillustrates one embodiment of a multi-speed transmission 200 accordingto the present disclosure. The transmission 200 includes an input shaft202 and an output shaft 204. The input shaft 202 and output shaft 204can be disposed along the same axis or centerline of the transmission200. In another aspect, the different shafts can be disposed alongdifferent axes or centerlines. In a further aspect, the different shaftscan be disposed parallel to one another, but along different axes orcenterlines. Other aspects can be appreciated by one skilled in the art.

The transmission 200 can also include a plurality of planetary gearsets.In the illustrated embodiment of FIG. 2, the transmission 200 includes afirst planetary gearset 206, a second planetary gearset 208, a thirdplanetary gearset 210, and a fourth planetary gearset 212. Eachplanetary gearset can be referred to as a simple or compound planetarygearset. For example, in some aspects, one or more of the plurality ofplanetary gearsets can be formed as an idler planetary gearset. In FIG.2, for instance, the first planetary gearset 206 is structurally setforth as an idler planetary gearset. In this example, an idler planetplanetary gearset can include a sun gear, a ring gear, a carrier, andtwo sets of pinion gears. One set of pinion gears can be rotationallycoupled with the sun gear and the other set of pinion gears can berotationally coupled to the ring gear. Both sets of pinion gears arecoupled to one another such that one pinion gear of the first set isrotationally coupled to one pinion gear of the second set. In thismanner, power can be transferred through the sun or ring gear via eachof the sets of pinion gears.

One or more of the plurality of planetary gearsets can be arranged indifferent locations within the transmission 200, but for sake ofsimplicity and in this particular example only, the planetary gearsetsare aligned in an axial direction consecutively in sequence (i.e.,first, second, third, and fourth between the input and output shafts).

The transmission 200 may also include a plurality of torque-transmittingor gearshifting mechanisms. For example, one or more of these mechanismscan include a clutch or brake. In one aspect, each of the plurality ofmechanisms is disposed within an outer housing of the transmission 200.In another aspect, however, one or more of the mechanisms may bedisposed outside of the housing. Each of the plurality of mechanisms canbe coupled to one or more of the plurality of planetary gearsets, whichwill be described further below.

In the embodiment of FIG. 2, the transmission 200 can include a firsttorque-transmitting mechanism 258 and a second torque-transmittingmechanism 260 that are configured to function as brakes (e.g., thetorque-transmitting mechanism is fixedly coupled to the outer housing ofthe transmission 200). Each brake can be configured as ashiftable-friction-locked disk brake, shiftable friction-locked bandbrake, shiftable form-locking claw or conical brake, or any other typeof known brake. The transmission 200 can include a thirdtorque-transmitting mechanism 262, a fourth torque-transmittingmechanism 264, and a fifth torque-transmitting mechanism 266 that areconfigured to function as clutches. These can be shiftablefriction-locked multi-disk clutches, shiftable form-locking claw orconical clutches, wet clutches, or any other known form of a clutch.With these five torque-transmitting mechanisms, selective shifting of atleast eight forward gears and at least one reverse gear is possible.

The transmission 200 of FIG. 2 may also include up to eight differentshafts, which is inclusive of the input shaft 202 and output shaft 204.Each of these shafts, designated as a first shaft 222, a second shaft224, a third shaft 226, a fourth shaft 236, a fifth shaft 246, and asixth shaft 248, are configured to be connected to one or more of theplurality of planetary gearsets or plurality of torque-transmittingmechanism between the input shaft 202 and output shaft 204.

In FIG. 2, the first planetary gearset 206 i.e., the idler planetplanetary gearset, can include a first sun gear 214, a first ring gear216, and a first carrier member 218 supports two sets of pinion gears.One set of pinion gears 268 is rotationally coupled to the sun gear 214and the other set of pinion gears 220 is rotationally coupled to thering gear 216. The second planetary gearset 208 can include a second sungear 228, a second ring gear 230, and a second carrier member 232 thatrotatably supports a set of pinion gears 234. The third planetarygearset 210 can include a third sun gear 238, a third ring gear 240, anda third carrier member 242 that rotatably supports a set of pinion gears244. The fourth planetary gearset 212 can include a fourth sun gear 250,a fourth ring gear 252, and a fourth carrier member 254 that rotatablysupports a set of pinion gears 256.

The transmission 200 is capable of transferring torque from the inputshaft 202 to the output shaft 204 in at least eight forward gears orratios and at least one reverse gear or ratio. Each of the forwardtorque ratios and the reverse torque ratios can be attained by theselective engagement of one or more of the torque-transmittingmechanisms (i.e., torque-transmitting mechanisms 258, 260, 262, 264, and266). Those skilled in the art will readily understand that a differentspeed ratio is associated with each torque ratio. Thus, at least eightforward speed ratios and at least one reverse speed ratio may beattained by transmission 200.

As for the transmission 200, kinematic coupling of the first planetarygearset 206 is shown in FIG. 2. The first sun gear 214 is coupled to thefirst shaft 222 for common rotation therewith. The first carrier member218 is coupled to the second shaft 224 for common rotation therewith.First ring gear 216 is coupled for common rotation with the third shaft226.

With respect to the second planetary gearset 208, the second sun gear228 is coupled to the first shaft 222 and first sun gear 214 for commonrotation therewith. The second ring gear 230 is coupled to the thirdshaft 236 for common rotation therewith. Second pinion gears 234 areconfigured to intermesh with the second sun gear 228 and second ringgear 230, and the second carrier member 232 is coupled for commonrotation with the input shaft 202.

The third sun gear 238 of the third planetary gearset 210 is coupled tothe sixth shaft 248 for common rotation therewith. The third ring gear240 is coupled to the fifth shaft 246, which is also coupled to thefourth sun gear 250, for common rotation therewith. Third pinion gears244 are configured to intermesh with the third sun gear 238 and thirdring gear 240, respectively. The third carrier member 242 is coupled forcommon rotation with the output shaft 204.

The kinematic relationship of the fourth planetary gearset 212 is suchthat the fourth sun gear 250 is coupled to the fifth shaft 246 and thirdring gear 240 for common rotation therewith. The fourth ring gear 252 iscoupled to the third shaft 226 for common rotation therewith. The fourthpinion gears 256 are configured to intermesh with the fourth sun gear250 and the fourth ring gear 252. The fourth carrier member 254 iscoupled to the output shaft 204 and third carrier member 242 for commonrotation therewith.

With regards to the kinematic coupling of the five torque-transmittingmechanisms to the previously described shafts, the multiple speedtransmission 200 of FIG. 2 provides that the first torque-transmittingmechanism 258 is arranged within the power flow between the first shaft222 and a housing G of the transmission 200. In this manner, the firsttorque-transmitting mechanism 258 is configured to act as a brake. Thesecond torque-transmitting mechanism 260 is arranged within the powerflow between the second shaft 224 and the housing G of the transmission200. In this manner, the second torque-transmitting mechanism 260 isconfigured to act as a brake. In this embodiment of the transmission 200therefore two of the five torque-transmitting mechanisms are configuredto act as a brake and the other three torque-transmitting mechanisms areconfigured to act as clutches.

The third torque-transmitting mechanism 262, for example, is arrangedwithin the power flow between the input shaft 202 and the fifth shaft246. The fourth torque-transmitting mechanism 264 is arranged within thepower flow between the fourth shaft 236 and the sixth shaft 248.Moreover, the fifth torque-transmitting mechanism 266 is arranged withinthe power flow between the fourth shaft 236 and the fifth shaft 246.

The kinematic couplings of the embodiment in FIG. 2 can further bedescribed with respect to the selective engagement of thetorque-transmitting mechanisms with respect to one or more components ofthe plurality of planetary gearsets. For example, in the transmission200, the first torque-transmitting mechanism 258 is selectivelyengageable to couple the first sun gear 214, the second sun gear 228,and the first shaft 222 to the housing G of the transmission 200. Thesecond torque-transmitting mechanism 260 is selectively engageable tocouple the first carrier member 218 and the second shaft 224 to thehousing G of the transmission 200. Moreover, the thirdtorque-transmitting mechanism 262 is selectively engageable to coupleinput shaft 202 and the second carrier member 232 to the fifth shaft246, third ring gear 240 and fourth sun gear 250. The fourthtorque-transmitting mechanism 264 is selectively engageable to couplefourth shaft 236 and second ring gear 230 to the third sun gear 238 andthe sixth shaft 248. Lastly, the fifth torque-transmitting mechanism 266is selectively engageable to couple the third ring gear 240 and thefifth shaft 246 to the second ring gear 230 and the fourth shaft 236.

Referring to FIG. 3, a schematic representation or stick diagramillustrates one embodiment of a multi-speed transmission 300 accordingto the present disclosure. The transmission 300 includes an input shaft302 and an output shaft 304. The input shaft 302 and output shaft 304can be disposed along the same axis or centerline of the transmission300. In another aspect, the different shafts can be disposed alongdifferent axes or centerlines. In a further aspect, the different shaftscan be disposed parallel to one another, but along different axes orcenterlines. Other aspect can be appreciated by one skilled in the art.

The transmission 300 can also include a plurality of planetary gearsets.In the illustrated embodiment of FIG. 3, the transmission 300 includes afirst planetary gearset 306, a second planetary gearset 308, a thirdplanetary gearset 310, and a fourth planetary gearset 312. Eachplanetary gearset can be referred to as a simple or compound planetarygearset. For example, in some aspects, one or more of the plurality ofplanetary gearsets can be formed as an idler planetary gearset. In FIG.3, for instance, the second planetary gearset 308 is structurally setforth as an idler planetary gearset. In this example, an idler planetplanetary gearset can include a sun gear, a ring gear, a carrier, andtwo sets of pinion gears. One set of pinion gears can be rotationallycoupled with the sun gear and the other set of pinion gears can berotationally coupled to the ring gear. Both sets of pinion gears arecoupled to one another such that one pinion gear of the first set isrotationally coupled to one pinion gear of the second set. In thismanner, power can be transferred through the sun or ring gear via eachof the sets of pinion gears.

One or more of the plurality of planetary gearsets can be arranged indifferent locations within the transmission 300, but for sake ofsimplicity and in this particular example only, the planetary gearsetsare aligned in an axial direction consecutively in sequence (i.e.,first, second, third, and fourth between the input and output shafts).

The transmission 300 may also include a plurality of torque-transmittingor gearshifting mechanisms. For example, one or more of these mechanismscan include a clutch or brake. In one aspect, each of the plurality ofmechanisms is disposed within an outer housing of the transmission 300.In another aspect, however, one or more of the mechanisms may bedisposed outside of the housing. Each of the plurality of mechanisms canbe coupled to one or more of the plurality of planetary gearsets, whichwill be described further below.

In the embodiment of FIG. 3, the transmission 300 can include a firsttorque-transmitting mechanism 358 and a second torque-transmittingmechanism 360 that are configured to function as brakes (e.g., thetorque-transmitting mechanism is fixedly coupled to the outer housing ofthe transmission 300). Each brake can be configured as ashiftable-friction-locked disk brake, shiftable friction-locked bandbrake, shiftable form-locking claw or conical brake, or any other typeof known brake. The transmission 300 can include a thirdtorque-transmitting mechanism 362, a fourth torque-transmittingmechanism 364, and a fifth torque-transmitting mechanism 366 that areconfigured to function as clutches. These can be shiftablefriction-locked multi-disk clutches, shiftable form-locking claw orconical clutches, wet clutches, or any other known form of a clutch.With these five torque-transmitting mechanisms, selective shifting of atleast eight forward gears and at least one reverse gear is possible.

The transmission 300 of FIG. 3 may also include up to eight differentshafts, which is inclusive of the input shaft 302 and output shaft 304.Each of these shafts, designated as a first shaft 322, a second shaft324, a third shaft 326, a fourth shaft 336, a fifth shaft 346, and asixth shaft 348, are configured to be connected to one or more of theplurality of planetary gearsets or plurality of torque-transmittingmechanism between the input shaft 302 and output shaft 304.

In FIG. 3, the first planetary gearset 306 can include a first sun gear314, a first ring gear 316, and a first carrier member 318 thatrotatably supports a set of pinion gears 320. The second planetarygearset 308, i.e., the idler planet planetary gearset, can include asecond sun gear 328, a second ring gear 330, and a second carrier member332 supports two sets of pinion gears. One set of pinion gears 268 isrotationally coupled to the sun gear 328 and the other set of piniongears 334 is rotationally coupled to the ring gear 330. The thirdplanetary gearset 310 can include a third sun gear 338, a third ringgear 340, and a third carrier member 342 that rotatably supports a setof pinion gears 344. The fourth planetary gearset 312 can include afourth sun gear 350, a fourth ring gear 352, and a fourth carrier member354 that rotatably supports a set of pinion gears 356.

The transmission 300 is capable of transferring torque from the inputshaft 302 to the output shaft 304 in at least eight forward gears orratios and at least one reverse gear or ratio. Each of the forwardtorque ratios and the reverse torque ratios can be attained by theselective engagement of one or more of the torque-transmittingmechanisms (i.e., torque-transmitting mechanisms 358, 360, 362, 364, and366). Those skilled in the art will readily understand that a differentspeed ratio is associated with each torque ratio. Thus, at least eightforward speed ratios and at least one reverse speed ratio may beattained by transmission 300.

As for the transmission 300, kinematic coupling of the first planetarygearset 306 is shown in FIG. 3. The first sun gear 314 is coupled to thefirst shaft 322 for common rotation therewith. The first carrier member318 is coupled to the third shaft 326 for common rotation therewith.First ring gear 316 is coupled for common rotation with the second shaft324.

With respect to the second planetary gearset 308, the second sun gear328 is coupled to the first shaft 322 and first sun gear 314 for commonrotation therewith. The second ring gear 330 is coupled to the inputshaft 302 for common rotation therewith. The second carrier member 332is coupled for common rotation with the fourth shaft 336.

The third sun gear 338 of the third planetary gearset 310 is coupled tothe sixth shaft 348 for common rotation therewith. The third ring gear340 is coupled to the fifth shaft 346, which is also coupled to thefourth sun gear 350, for common rotation therewith. Third pinion gears344 are configured to intermesh with the third sun gear 338 and thirdring gear 340, respectively. The third carrier member 342 is coupled forcommon rotation with the output shaft 204 and fourth carrier member 354.

The kinematic relationship of the fourth planetary gearset 312 is suchthat the fourth sun gear 350 is coupled to the fifth shaft 346 and thirdring gear 340 for common rotation therewith. The fourth ring gear 352 iscoupled to the third shaft 326 for common rotation therewith. The fourthpinion gears 356 are configured to intermesh with the fourth sun gear350 and the fourth ring gear 352. The fourth carrier member 354 iscoupled to the output shaft 304 and third carrier member 342 for commonrotation therewith.

With regards to the kinematic coupling of the five torque-transmittingmechanisms to the previously described shafts, the multiple speedtransmission 300 of FIG. 3 provides that the first torque-transmittingmechanism 358 is arranged within the power flow between the first shaft322 and a housing G of the transmission 300. In this manner, the firsttorque-transmitting mechanism 358 is configured to act as a brake. Thesecond torque-transmitting mechanism 360 is arranged within the powerflow between the second shaft 324 and the housing G of the transmission300. In this manner, the second torque-transmitting mechanism 360 isconfigured to act as a brake. In this embodiment of the transmission 300therefore two of the five torque-transmitting mechanisms are configuredto act as a brake and the other three torque-transmitting mechanisms areconfigured to act as clutches.

The third torque-transmitting mechanism 362, for example, is arrangedwithin the power flow between the input shaft 302 and the fifth shaft346. The fourth torque-transmitting mechanism 364 is arranged within thepower flow between the fourth shaft 336 and the sixth shaft 348.Moreover, the fifth torque-transmitting mechanism 366 is arranged withinthe power flow between the fourth shaft 336 and the fifth shaft 346.

The kinematic couplings of the embodiment in FIG. 3 can further bedescribed with respect to the selective engagement of thetorque-transmitting mechanisms with respect to one or more components ofthe plurality of planetary gearsets. For example, in the transmission300, the first torque-transmitting mechanism 358 is selectivelyengageable to couple the first sun gear 314, the second sun gear 328,and the first shaft 322 to the housing G of the transmission 300. Thesecond torque-transmitting mechanism 360 is selectively engageable tocouple the first ring gear 316 and the second shaft 324 to the housing Gof the transmission 300. Moreover, the third torque-transmittingmechanism 362 is selectively engageable to couple input shaft 302 andthe second ring gear 330 to the fifth shaft 346, third ring gear 340 andfourth sun gear 350. The fourth torque-transmitting mechanism 364 isselectively engageable to couple fourth shaft 336 and second carriermember 332 to the third sun gear 338 and the sixth shaft 348. Lastly,the fifth torque-transmitting mechanism 366 is selectively engageable tocouple the third ring gear 340 and the fifth shaft 346 to the secondcarrier member 332 and the fourth shaft 336.

As previously described, the aforementioned embodiment is capable oftransmitting torque from a respective input shaft to a respective outputshaft in at least eight forward torque ratios and one reverse torqueratio. Referring to FIG. 4, one example of a truth table is shownrepresenting a state of engagement of various torque transmittingmechanisms in each of the available forward and reverse speeds or gearratios of the transmissions illustrated in FIGS. 2 and 3. It is to beunderstood that FIG. 4 is only one example of any number of truth tablespossible for achieving at least eight forward ratios and one reverseratio, and one skilled in the art is capable of configuring diameters,gear tooth counts, and gear configurations to achieve other ratios.

In the example of FIG. 4, the reverse ratio (rev) can be achieved by theselective engagement of the torque-transmitting mechanisms as set forthin the table. As shown, the first torque transmitting mechanism (B1),second torque-transmitting mechanism (B2), and fourthtorque-transmitting mechanism (C4) are selectively engaged to establishthe reverse ratio. Thus, in transmission 200 of FIG. 2, the selectiveengagement of mechanisms 258, 260, and 264 can establish the reverseratio.

In neutral (Neu), none of the torque-transmitting mechanisms carrytorque. One or more of the torque-transmitting mechanisms, however, maybe engaged in neutral but not carrying torque. For example, the firstand fourth torque-transmitting mechanisms can be engaged in neutral,thereby resulting in the fifth torque-transmitting mechanism beingdisengaged between a shift between the one reverse ratio and neutral.

A first forward ratio (shown as 1st) in the table of FIG. 4 is achievedby engaging both brakes and one of the clutches. In FIG. 2, for example,the first torque-transmitting mechanism 258, the secondtorque-transmitting mechanism 260, and the third torque-transmittingmechanism 262 are engaged. Thus, when transitioning between neutral andthe first forward range, the first and second torque-transmittingmechanisms may already be engaged, and the third torque-transmittingmechanism is selectively engaged.

In a second or subsequent forward ratio, indicated as 2nd in FIG. 4, thefirst torque-transmitting mechanism, the second torque-transmittingmechanism, and the fifth torque-transmitting mechanism are selectivelyengaged. Therefore, when transitioning between the first forward ratioand the second forward ratio, the third torque-transmitting mechanism isreleased and the fifth torque-transmitting mechanism is engaged.

In a third or subsequent forward ratio, indicated as 3rd forward ratioin FIG. 4, the second torque-transmitting mechanism, thirdtorque-transmitting mechanism, and fifth torque-transmitting mechanismare engaged. To transition from the second forward ratio to the thirdforward ratio, for example, the first torque-transmitting mechanism isreleased and the third torque-transmitting mechanism is engaged.

In a fourth or the next subsequent forward ratio, indicated as 4th inFIG. 4, the second torque-transmitting mechanism, fourthtorque-transmitting mechanism, and fifth torque-transmitting mechanismare engaged. Thus, to transition from the third forward ratio andupshift to the fourth forward ratio, the third torque-transmittingmechanism is released and the fourth torque-transmitting mechanism isengaged.

In a fifth or the next subsequent forward ratio, indicated as 5th inFIG. 4, the second torque-transmitting mechanism, thirdtorque-transmitting mechanism, and fourth torque-transmitting mechanismare engaged. Thus, to transition from the fourth forward ratio andupshift to the fifth forward ratio, the fifth torque-transmittingmechanism is released and the third torque-transmitting mechanism isengaged.

In a sixth or the next subsequent forward ratio, indicated as 6th inFIG. 4, the third torque-transmitting mechanism, fourthtorque-transmitting mechanism, and fifth torque-transmitting mechanismare engaged. Thus, to transition from the fifth forward ratio andupshift to the sixth forward ratio, the second torque-transmittingmechanism is released and the fifth torque-transmitting mechanism isengaged.

In a seventh or the next subsequent forward ratio, indicated as 7th inFIG. 4, the first torque-transmitting mechanism, thirdtorque-transmitting mechanism, and fourth torque-transmitting mechanismare engaged. Thus, to transition from the sixth forward ratio andupshift to the seventh forward ratio, the fifth torque-transmittingmechanism is released and the first torque-transmitting mechanism isengaged.

In an eighth or the next subsequent forward ratio, indicated as 8th inFIG. 4, the first torque-transmitting mechanism, fourthtorque-transmitting mechanism, and fifth torque-transmitting mechanismare engaged. Thus, to transition from the seventh forward ratio andupshift to the eighth forward ratio, the third torque-transmittingmechanism is released and the fifth torque-transmitting mechanism isengaged.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above), and severalpower-on skip-shifts that are single-transition are possible (e.g. from1st to 3rd or 3rd to 1st).

While exemplary embodiments incorporating the principles of the presentdisclosure have been disclosed hereinabove, the present disclosure isnot limited to the disclosed embodiments. Instead, this application isintended to cover any variations, uses, or adaptations of the disclosureusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this disclosure pertains andwhich fall within the limits of the appended claims.

1. A multiple speed transmission, comprising: an input member, an outputmember; first, second, third and fourth planetary gearsets each havingfirst, second and third members; a plurality of interconnecting memberseach connected between at least one of the first, second, third, andfourth planetary gearsets and at least another of the first, second,third, and fourth planetary gearsets; a first torque-transmittingmechanism selectively engageable to interconnect the first member of thefirst planetary gearset with a stationary member; a secondtorque-transmitting mechanism selectively engageable to interconnect thesecond member of the first planetary gearset with the stationary member;a third torque-transmitting mechanism selectively engageable tointerconnect the second member of the second planetary gearset with thefirst member of the fourth planetary gearset; a fourthtorque-transmitting mechanism selectively engageable to interconnect thethird member of the second planetary gearset with the first member ofthe third planetary gearset; and a fifth torque-transmitting mechanismselectively engageable to interconnect the third member of the secondplanetary gearset with the third member of the third planetary gearsetand the first member of the fourth planetary gearset; wherein the torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish at least eight forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember.
 2. The multiple speed transmission of claim 1, wherein the inputmember is continuously interconnected with the second member of thesecond planetary gearset and the output member is continuouslyinterconnected with the second member of the third planetary gearset andthe second member of the fourth planetary gearset.
 3. The multiple speedtransmission of claim 1, wherein the plurality of interconnectingmembers includes a first interconnecting member continuouslyinterconnecting the first member of the first planetary gearset with thefirst member of the second planetary gearset.
 4. The multiple speedtransmission of claim 1, wherein the plurality of interconnectingmembers includes a second interconnecting member continuouslyinterconnecting the third member of the first planetary gearset with thethird member of the fourth planetary gearset.
 5. The multiple speedtransmission of claim 1, wherein the plurality of interconnectingmembers includes a third interconnecting member that directly connectsthe second member of the first planetary gearset to the stationarymember.
 6. The multiple speed transmission of claim 1, wherein theplurality of interconnecting members includes a fourth interconnectingmember continuously connected to the third member of the secondplanetary gearset.
 7. The multiple speed transmission of claim 1,wherein the plurality of interconnecting members includes a fifthinterconnecting member continuously interconnecting the third member ofthe third planetary gearset to the first member of the fourth planetarygearset.
 8. The multiple speed transmission of claim 1, wherein theplurality of interconnecting members includes a sixth interconnectingmember continuously connected to the first member of the third planetarygearset.
 9. The multiple speed transmission of claim 1, wherein theplurality of interconnecting members includes a seventh interconnectingmember continuously connected to the first members of the firstplanetary gearset and the second planetary gearset.
 10. The multiplespeed transmission of claim 1, wherein the first planetary gearsetcomprises an idler planetary gearset having a first set of pinion gearsand a second set of pinions gears.
 11. A multiple speed transmission,comprising: an input member, an output member; first, second, third andfourth planetary gearsets each having a sun gear, a carrier member, anda ring gear, wherein at least one of the first, second, third and fourthplanetary gearsets comprises an idler planetary gearset and the inputmember and the output member are each interconnected to at least one ofthe first, second, third, and fourth planetary gearsets; a firsttorque-transmitting mechanism selectively engageable to interconnect thesun gear of the first planetary gearset and the sun gear of the secondplanetary gearset with a stationary member; a second torque-transmittingmechanism selectively engageable to interconnect the carrier member ofthe first planetary gearset with the stationary member, a thirdtorque-transmitting mechanism selectively engageable to interconnect thecarrier member of the second planetary gearset with the ring gear of thethird planetary gearset and the sun gear of the fourth planetarygearset; a fourth torque-transmitting mechanism selectively engageableto interconnect the sun gear of the third planetary gearset with thering gear of the second planetary gearset; and a fifthtorque-transmitting mechanism selectively engageable to interconnect thering gear of the third planetary gearset and the sun gear of the fourthplanetary gearset with the ring gear of the second planetary gearset;wherein the torque transmitting mechanisms are selectively engageable incombinations of at least three to establish at least eight forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 12. The multiple speed transmission of claim 11,wherein the input member is continuously interconnected with the carriermember of the second planetary gearset and the output member iscontinuously interconnected with the ring gear of the third planetarygearset and the carrier member of the fourth planetary gearset.
 13. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a first interconnecting membercontinuously interconnecting the sun gear of the first planetary gearsetwith the sun gear of the second planetary gearset.
 14. The multiplespeed transmission of claim 11, wherein the plurality of interconnectingmembers includes a second interconnecting member directly connecting thecarrier member of the first planetary gearset to the stationary member.15. The multiple speed transmission of claim 11, wherein the pluralityof interconnecting members includes a third interconnecting membercontinuously interconnecting the ring gear of the first planetarygearset to the ring gear of the fourth planetary gearset.
 16. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a fourth interconnecting membercontinuously connected to the ring gear of the second planetary gearset.17. The multiple speed transmission of claim 11, wherein the pluralityof interconnecting members includes a fifth interconnecting membercontinuously interconnecting the ring gear of the third planetarygearset to the sun gear of the fourth planetary gearset
 18. The multiplespeed transmission of claim 11, wherein the plurality of interconnectingmembers includes a sixth interconnecting member continuously connectedto the sun gear of the third planetary gearset.
 19. A multiple speedtransmission, comprising: an input member, an output member; first,second, third and fourth planetary gearsets each having a sun gear, acarrier member, and a ring gear, the input member and the output memberare each interconnected to at least one of the first, second, third, andfourth planetary gearsets; a first torque-transmitting mechanismselectively engageable to interconnect the sun gear of the firstplanetary gearset and the sun gear of the second planetary gearset witha stationary member; a second torque-transmitting mechanism selectivelyengageable to interconnect the ring gear of the first planetary gearsetwith the stationary member; a third torque-transmitting mechanismselectively engageable to interconnect the ring gear of the secondplanetary gearset with the sun gear of the fourth planetary gearset andthe ring gear of the third planetary gearset; a fourthtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the third planetary gearset with the carrier member of thesecond planetary gearset; a fifth torque-transmitting mechanismselectively engageable to interconnect the third ring gear of the thirdplanetary gearset with the carrier member of the second planetarygearset; a first interconnecting member of the plurality of interconnectmembers continuously interconnecting the sun gear of the first planetarygearset with the sun gear of the second planetary gearset; a secondinterconnecting member of the plurality of interconnect memberscontinuously connected to the ring gear of the first planetary gearset;a third interconnecting member of the plurality of interconnect membersdirectly connects the carrier member of the first planetary gearset tothe ring gear of the fourth planetary gearset; a fourth interconnectingmember of the plurality of interconnect members continuously connectedto the carrier member of the second planetary gearset; a fifthinterconnecting member of the plurality of interconnect memberscontinuously interconnecting the ring gear of the third planetarygearset with the sun gear of the fourth planetary gearset; a sixthinterconnecting member of the plurality of interconnect memberscontinuously connected to the sun gear of the third planetary gearset;and wherein the second planetary gearset comprises an idler planetarygearset; further wherein the torque transmitting mechanisms areselectively engageable in combinations of at least three to establish atleast eight forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.
 20. The multiple speedtransmission of claim 19, wherein when shifting from one forward speedratio into one of a successive higher and a successive lower forwardspeed ratio causes a single one of the first, the second, the third, thefourth, and the fifth torque transmitting mechanisms to disengage and asingle one of the first, the second, the third, the fourth, and thefifth torque transmitting mechanisms to engage.